There is a need for low bend loss optical fibers, particularly for optical fibers utilized in so-called “access” and fiber to the premises (FTTx) optical networks. Optical fiber is often deployed in such networks in a manner that induces bend losses in optical signals transmitted through the optical fiber. Some applications that can impose physical demands, such as tight bend radii, compression of optical fiber, etc., that induce bend losses include the deployment of optical fiber in optical drop cable assemblies, distribution cables with Factory Installed Termination Systems (FITS) and slack loops, small bend radius multiports located in cabinets that connect feeder and distribution cables, and jumpers in Network Access Points between distribution and drop cables. It has been difficult in some optical fiber designs to achieve both low bend loss and low cable cutoff wavelength at the same time.
High power systems often suffer from non-linear optical effects, including self-phase modulation, four-wave-mixing, cross-phase modulation, and non-linear scattering processes, all of which can cause degradation of signals in high powered systems. In some applications, optical power levels of 1 mW or less are sensitive to non-linear effects, so non-linear effects may still be an important consideration in low power systems. In addition, other optical fiber attributes, such as attenuation, contribute to the degradation of the signal. Generally, an optical waveguide fiber having a large effective area (A eff) or large mode field diameter (MFD) reduces signal-degrading non-linear optical effects. Increasing the effective area of an optical waveguide fiber, however, typically results in an increase in macrobending- and microbending-induced losses, which attenuate signal transmission through a fiber. The need for low microbending losses become increasingly important over long transmission distances (e.g. 100 km or more) and in systems with large spacing between regenerators, amplifiers, transmitters and/or receivers. It would be desirable to develop an optical fiber having a large effective area (A eff) and low bend losses.